Method for manufacturing of a detachable joint for artificial teeth, and a structural member assembly therefor

ABSTRACT

The invention relates to a method for producing a releasable connection for an artificial tooth, consisting of a lower crown permanently securable on a tooth or on a pillar projecting from the jaw, and of an upper crown surrounding the lower crown and serving as a support for teeth prostheses, the connection pivotally supporting a locking axle having a segment-like cutout, the axle is rotatable by means of a locking blade insertable into the upper surface of the upper crown and cooperating with a partially cylindrical recess in a locking strip which is connected to the lower crown whereby the lower crown together with the locking strip is modelled on a positive model of the tooth or of the pillar and the upper crown is modelled on the casting thereof.

United States Patent Just METHOD FOR MANUFACTURING OF A DETACHABLE JOINT FOR ARTIFICIAL TEETH, AND A STRUCTURAL MEMBER ASSEMBLY THEREFOR Inventor: Franz-Peter Just, Bremen, Germany Assignee: Hans Grafelmann, Bremen,

Germany Filed: Aug. 26, 1974 Appl. No.: 500,561

Related US. Application Data [63] Continuation of Ser. No. 324,183, Jan. 16, 1973,

abandoned.

[52] US. Cl. 32/5 [51] Int. Cl. A61C 13/22 [58] Field of Search 32/5, 6, 7

[56] References Cited UNITED STATES PATENTS 1,673,286 6/1928 Inque 32/5 Primary Examiner-Robert Peshock [57] ABSTRACT The invention relates to a method for producing a releasable connection for an artificial tooth, consisting of a lower crown permanently securable on a tooth or on a pillar projecting from the jaw, and of an upper crown surrounding the lower crown and serving as a support for teeth prostheses, the connection pivotally supporting a locking axle having a segment-like cutout, the axle is rotatable by means of a locking blade insertable into the upper surface of the upper crown and cooperating with a partially cylindrical recess in a locking strip which is connected to the lower crown whereby the lower crown together with the locking strip is modelled on a positive mode] of the tooth or of the pillar and the upper crown is modelled on the casting thereof.

12 Claims, 8 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of2 US. Patent Dec. 30, 1975 Sheet2of2 3,928,912

METHOD FOR MANUFACTURING OF A DETACIIABLE JOINT FOR ARTIFICIAL TEETH, AND A STRUCTURAL MEMBER ASSEMBLY THEREFOR This is a continuation of application Ser. No. 324,183, filed Jan. 16, 1973, and now abandoned.

Hitherto, the procedure has been such that in modelling the lower crown the locking strip has been shaped of modelling wax and that in modelling the upper crown, a piece of wire instead of the later-on locking axle has been inserted and the upper crown has been modelled without the locking blade, and that upon the casting of the upper crown in a separate method step of modelling, forming a negative form and casting, the locking blade was produced. Such method is extremely time consuming and, accordingly, costly.

The basis of this invention is, therefore, the problem how to simplify the carrying-out of the above described method and how to facilitate the production of a releasable connection for an artificial tooth of the type 'in question and also how to reduce its cost.

According to this invention, this problem is solved so that during the modelling of the lower crown there is shaped a prefabricated locking strip having a recess and being cast or integrally molded therewith, that on the completed lower crown, in engagement with the locking strip, is mounted a finished component consisting of a locking axle and a locking blade, the upper crown while incorporating the finished component being modelled on the lower crown, the finished component being removed and a negative form being poured-in or cast, and subsequently the upper crown is cast into the negative form and the finished component being put therein.

The prefabricated locking strip saves the time consuming individual stretching on the lower crown pattern without preventing an individual selection of the position of the locking strip on the periphery of the lower crown. Similarly, the prefabrication and employment of a finished component consisting of a locking axle and of a locking blade facilitates the modelling of the upper crown and saves the third modelling and casting process for the locking blade. Moreover, it is guaranteed that the locking blade will always maintain all technically indispensable qualities without putting on more than what is unconditionally necessary.

Preferably, a prefabricated locking counterpart which at least partially surrounds the finished component is secured together with the finished component on the completed lower crown and takes part in the modelling of the upper crown. While, the finished component as preferred, is always in its final form, namely the locking axle consisting of steel and the locking blade of gold, for example, the locking counterpart (as well as the prefabricated locking strip) is advantageously made of a synthetic material which during the casting of the crown as well as the modelling wax are melted out. The locking counterpiece which is premodelled to a certain degree guarantees that the finished component in the completed upper crown is correctly supported and that it has a proper contact surface. Furthermore, arresting hoses and recesses which arrest the locking blade in the closing position of the locking axle, can be also prefabricated. The same is applicable for a cam which is provided on the locking axle in the region of the locking blade, the cam coopertting with a partially circular recess in the locking counterpiece in order to limit the rotary movement of the locking member.

The segment-like cutaway portion in the locking axle is made preferably only upon the final insertion of the final component into the upper crown.

In the following the invention is explained in more detail with the aid of an exemplary embodiment of a releasable connection for an. artificial tooth of the above described type. In the drawings,

FIG. 1 is a perspective plane view of a completed lower crown;

FIG. 2 is also a perspective view, in the same direction, of an upper crown superimposed on the lower crown of FIG. 1, with open locking means;

FIG. 3 is a perspective view of the arrangement of FIG. 2 showing, however, the open locking blade from the rear;

FIG. 4 is an enlarged illustration of the locking strip on the lower crown with the locking axle supported in the upper crown as well as the locking blade in the closed (locked) position;

FIG. 5 is a cutaway illustration of FIG. 4 in an open position of the locking axle;

FIG. 6 is a perspective illustration of a finished component, prior to its application;

FIG. 7 is a perspective illustration of a locking strip or of a pattern thereof; and

FIG. 8 is a perspective rear view of a locking counterpart as prefabricated for modelling.

In FIGS. 1 to 3, a tooth l which can be also substituted for an implantated pillar or stud projecting from the jaw is merely indicated. The lower crown 2 has been produced so that during its modelling on the cast of the tooth or pillar, a prefabricated locking strip 3 (FIG. 7) having partially cylindrical recess 4 had been employed. In the example, the locking strip 3 consists of a synthetic material which had been burned during the casting so that the locking strip 3a which forms a part of the completed lower crown 2 corresponds as to its form to the prefabricated locking strip 3. As it can be clearly seen in the drawings, the side flanks of the strip converge slightly upwardly in order to insure a firm seat of the upper crown while maintaining an easy releasability thereof.

On the completed lower crown 2 is first for the production of a negative form modelled the upper crown 5 which in FIGS. 2 and 3 is illustrated in its finished state. Besides, a finished component 6 (FIG. 6) is put together with a prefabricated locking counterpiece 7 (FIG. 8) and in the later-on locking position is secured on the lower crown 2 with the aid of the modelling material. The locking counterpiece 7 has an opposite surface 8 not seen in FIG. 8 for the locking blade 9 as well as an arresting recess 10 for the arresting boss 11, and a guiding portion 12 for the locking axle 13. Furthermore, the locking counterpiece 7 consisting of a synthetic material which had been fired or burned during casting has just as the prefabricated locking strip 3, a partially circular cutout 14 which upon casting cooperates with a cam 15 which is provided on the locking axle 13 in the region of the locking blade 9.

The finished component 6 consists preferably of final materials, that is of a platinum alloy locking axle l3 and of a locking blade 9 of tooth gold.

Of the latter material consists also an attachment 16 extending in axial direction on the other side of the locking blade 9 to faiclitate the manipulation of the 3 finished component 6 together with the inserted locking counterpiece 7 during the modelling of the upper crown 5, and serves as a riveting abutment.

Upon the modelling of the upper crown which, contrary to the illustration in FIGS. 2 and 3, can of course consist of a pice which bridges several teeth and if necessary, can cooperate with an additional lower crown 2, the finished component 6 is pulled out from the model (and from the locking counterpiece 7) and subsequently a negative form is produced and a casting made.

Upon the casting of the upper crown the finished component 6 is inserted into the upper crown 5 (which is not united with the lower crown 2) and is riveted at the end thereof facing the locking blade 9, in maintaining its rotatability the range of which is defined by the recess 14 and the cam 15. Then a partially cylindrical cutout 17 is made in the locking axle 13, which according to FIGS. 4 and 5, makes it possible that in the swung-up open condition of the locking blade 9 the upper crown 5 can be withdrawn from the lower crown 2 whereas in the swung-in condition of the locking blade 9 (in which the arresting boss 11 engages the arresting recess a; FIGS. 2 and 3) the part 18 of the locking axle 13 remaining in the region of the cutout 17 engages the cutout or recess 4a of the locking axle 3a and the upper crown 5 is latched against loosening from the lower crown 2.

I claim:

1. Prefabricated modeling aids for use in preparing an artificial tooth of the kind comprising two crowns releasably secured together and including a first crown cast from a first crown mold prepared from a first crown mold pattern; and a second crown cast from a second crown mold prepared from a second crown mold pattern; said patterns being modeled to conform with each other and the requirements of the jaw whereby the second crown fits over the first crown and is releasably secured thereto; the first crown including a locking strip having a portion removed to define a locking strip recess; the second crown including a rotatably mounted locking part for interengaging with the locking strip in the first crown,

said modeling aids comprising:

a prefabricated locking part for use in producing in said second crown mold pattern a guide means for said locking part, said locking part being operable for use in said artificial tooth and including a prefabricated locking axle and a prefabricated locking blade secured to said prefabricated locking axle, whereby said axle may be rotated to interengage said locking strip.

2. Prefabricated modeling aids as claimed in claim 1, and a locking blade counterpart modeling aid securable to said second crown mold pattern to provide for a complementary arresting area for said locking blade on said second crown.

3. Prefabricated modeling aids as claimed in claim 2,

said prefabricated locking axle further including a cam,

said locking blade counterpart defining a partially circular recess resulting in a partially circular recess defined in said second crown which cooperates with said cam to limit the rotation of said locking axle.

4. Prefabricated modeling aids as claimed in claim 1,

said locking blade being secured to said locking axle at a substantially perpendicular angle whereby said locking blade is positioned close to said second crown in the position wherein said locking axle is interengaged with said locking strip.

5. Prefabricated modeling aids as claimed in claim 1 wherein said locking blade further comprises an arresting boss whereby said first crown mold pattern is provided with complementary arresting recesses.

6. In a method for producing a releasable connection in an artificial tooth, the artificial tooth being of the kind that comprises a lower crown securable on a tooth or on a pillar post projecting from thejaw and an upper crown which fits releasably over the lower crown, the lower crown being cast in a lower crown mold prepared from a lower crown mold pattern formed to conform to the requirements of the jaw and the artificial tooth, the upper crown being cast in an upper crown mold prepared from an upper crown mold pattern formed to conform to the requirements of the jaw and to fit over said lower crown, said lower crown including a locking strip having a portion removed to define a locking strip recess, a guide means defined in the cast upper crown, a locking part including a locking blade and a locking axle, said locking blade secured to said locking axle, said locking axle having a recess portion removed to define a locking axle recess and being rotatably mounted in said guide means whereby, by use of said locking blade, said locking axle may be rotated between opposite locking and unlocking positions, respectively, and said locking axle and said locking strip recess being so disposed relative to each other within the tooth so that when said locking axle is in the locking position it is at least partially engaged in said locking strip recess and, respectively, when said locking axle is in said unlocking position said locking strip recess and said locking axle recess are coincidental, whereby said locking axle is disengaged from said locking strip,

the steps comprising:

preparing said upper crown pattern on said lower crown, to fit over said lower crown and using a prefabricated locking part, operable for use in said upper crown, to provide for, and properly locate guide means for said locking part in said upper crown; casting said upper crown;

subsequently inserting said prefabricated locking axle into said guide means of said upper crown; and removing said recess portion from said prefabricated locking axle for use in said artificial tooth.

7. In a method as claimed in claim 6 further comprising the step of using the lower crown shaped cavity formed in said upper crown by the modeling of said upper crown pattern over said lower crown, as a guide for removing said portion from said locking axle.

8. In a method as claimed in claim 6 further comprising the step of preparing said lower crown pattern using a prefabricated locking strip as part of the lower crown pattern by securing the prefabricated locking strip to said lower crown pattern prior to preparing said blade, on the upper crown which arresting area will support and hold the locking blade.

12. In a method as claimed in claim 11, said locking axle including a cam and said locking blade counterpart modeling aid defining a partially circular recess to form a partially circular recess in said upper crown,

said cam and said partially circular recess in said upper crown, cooperating to limit the rotation of said locking axle. 

1. Prefabricated modeling aids for use in preparing an artificial tooth of the kind comprising two crowns releasably secured together and including a first crown cast from a first crown mold prepared from a first crown mold pattern; and a second crown cast from a second crown mold prepared from a second crown mold pattern; said patterns being modeled to conform with each other and the requirements of the jaw whereby the second crown fits over the first crown and is releasably secured thereto; the first crown including a locking strip having a portion removed to define a locking strip recess; the second crown including a rotatably mounted locking part for interengaging with the locking strip in the first crown, said modeling aids comprising: a prefabricated locking part for use in producing in said second crown mold pattern a guide means for said locking part, said locking part being operable for use in said artificial tooth and including a prefabricated locking axle and a prefabricated locking blade secured to said prefabricated locking axle, whereby said axle may be rotated to interengage said locking strip.
 2. Prefabricated modeling aids as claimed in claim 1, and a locking blade counterpart modeling aid securable to said second crown mold pattern to provide for a complementary arresting area for said locking blade on said second crown.
 3. Prefabricated modeling aids as claimed in claim 2, said prefabricated locking axle further including a cam, said locking blade counterpart defining a partially circular recess resulting in a partially circular recess defined in said second crown which cooperates with said cam to limit the rotation of said locking axle.
 4. Prefabricated modeling aids as claimed in claim 1, said locking blade being secured to said locking axle at a substantially perpendicular angle whereby said locking blade is positioned close to said second crown in the position wherein said locking axle is interengaged with said locking strip.
 5. Prefabricated modeling aids as claimed in claim 1 wherein said locking blade further comprises an arresting boss whereby said first crown mold pattern is provided with complementary arresting recesses.
 6. In a method for producing a releasable connection in an artificial tooth, the artificial tooth being of the kind that comprises a lower crown securable on a tooth or on a pillar post projecting from the jaw and an upper crown which fits releasably over the lower crown, the lower crown being cast in a lower crown mold prepared from a lower crown mold pattern formed to conform to the requirements of the jaw and the artificial tooth, the upper crown being cast iN an upper crown mold prepared from an upper crown mold pattern formed to conform to the requirements of the jaw and to fit over said lower crown, said lower crown including a locking strip having a portion removed to define a locking strip recess, a guide means defined in the cast upper crown, a locking part including a locking blade and a locking axle, said locking blade secured to said locking axle, said locking axle having a recess portion removed to define a locking axle recess and being rotatably mounted in said guide means whereby, by use of said locking blade, said locking axle may be rotated between opposite locking and unlocking positions, respectively, and said locking axle and said locking strip recess being so disposed relative to each other within the tooth so that when said locking axle is in the locking position it is at least partially engaged in said locking strip recess and, respectively, when said locking axle is in said unlocking position said locking strip recess and said locking axle recess are coincidental, whereby said locking axle is disengaged from said locking strip, the steps comprising: preparing said upper crown pattern on said lower crown, to fit over said lower crown and using a prefabricated locking part, operable for use in said upper crown, to provide for, and properly locate guide means for said locking part in said upper crown; casting said upper crown; subsequently inserting said prefabricated locking axle into said guide means of said upper crown; and removing said recess portion from said prefabricated locking axle for use in said artificial tooth.
 7. In a method as claimed in claim 6 further comprising the step of using the lower crown shaped cavity formed in said upper crown by the modeling of said upper crown pattern over said lower crown, as a guide for removing said portion from said locking axle.
 8. In a method as claimed in claim 6 further comprising the step of preparing said lower crown pattern using a prefabricated locking strip as part of the lower crown pattern by securing the prefabricated locking strip to said lower crown pattern prior to preparing said lower crown mold therefrom.
 9. In a method as claimed in claim 6 further comprising the step of preparing said upper crown pattern to include arresting recesses for arresting bosses by providing said prefabricated locking blade with an arresting boss and using the boss as a modeling aid to form complementary arresting recesses.
 10. Prefabricated modeling aids as claimed in claim 1 further comprising a prefabricated locking strip for use on said second crown mold pattern whereby the second crown mold is formed, in part, on said prefabricated locking strip.
 11. In a method as claimed in claim 6, further comprising the step of securing a locking blade counterpart modeling aid to said upper crown mold pattern to provide for a complementary arresting area for said locking blade, on the upper crown which arresting area will support and hold the locking blade.
 12. In a method as claimed in claim 11, said locking axle including a cam and said locking blade counterpart modeling aid defining a partially circular recess to form a partially circular recess in said upper crown, said cam and said partially circular recess in said upper crown, cooperating to limit the rotation of said locking axle. 